One linux command per day (30) : chown command in detail

chown changes the owner of a specified file to a specified user or group, which can be a user name or user ID; A group can be a group name or group ID; The file is a whitespace separated list of files to change permissions. Wildcards are supported. System administrators often use the chown command to give a user permission to use a file after copying it to another user's directory.

1. Command format:

chown [option]... [owner][:[group]] file...

2. Command functions:

Change the owner and group of files via chown. When you change the owner of a file or the group to which it belongs, you can use the user name and user identifier Settings. Regular users cannot change their files to other owners. Its operation permission 1 as the administrator.

3. Command parameters:

Necessary parameters:

-c displays information about the changed part -f ignores error messages -h fixes symlinks -R handles all files in the specified directory and its subdirectories -v displays detailed processing information -deference works on the pointing of symbolic links, not the link file itself

Selection parameters:

- reference = < Directory or file > Use the specified directory/file as a reference, and set the operating file/directory to the same owner and group as the reference file/directory - from = < Current user: current group > Only if the current user and group are the same as the specified user and group --help displays help --version displays version information

4. Examples of use:

Example 1: change owner and group

Command:

chown mail:mail log2012.log

Output:

[root@localhost test6]# ll
---xr--r-- 1 root users 302108 11-30 08:39 linklog.log
---xr--r-- 1 root users 302108 11-30 08:39 log2012.log
-rw-r--r-- 1 root users   61 11-30 08:39 log2013.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2014.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2015.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2016.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2017.log
[root@localhost test6]# chown mail:mail log2012.log 
[root@localhost test6]# ll
---xr--r-- 1 root users 302108 11-30 08:39 linklog.log
---xr--r-- 1 mail mail 302108 11-30 08:39 log2012.log
-rw-r--r-- 1 root users   61 11-30 08:39 log2013.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2014.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2015.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2016.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2017.log
[root@localhost test6]#

Example 2: changing file owners and groups

Command:

chown root: log2012.log

Output:

[root@localhost test6]# ll
 A total of  604
---xr--r-- 1 root users 302108 11-30 08:39 linklog.log
---xr--r-- 1 mail mail 302108 11-30 08:39 log2012.log
-rw-r--r-- 1 root users   61 11-30 08:39 log2013.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2014.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2015.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2016.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2017.log
[root@localhost test6]# chown root: log2012.log 
[root@localhost test6]# ll
 A total of  604
---xr--r-- 1 root users 302108 11-30 08:39 linklog.log
---xr--r-- 1 root root 302108 11-30 08:39 log2012.log
-rw-r--r-- 1 root users   61 11-30 08:39 log2013.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2014.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2015.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2016.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2017.log
[root@localhost test6]#

Example 3: changing file groups

Command:

chown :mail log2012.log

Output:

[root@localhost test6]# ll
 A total of  604
---xr--r-- 1 root users 302108 11-30 08:39 linklog.log
---xr--r-- 1 root root 302108 11-30 08:39 log2012.log
-rw-r--r-- 1 root users   61 11-30 08:39 log2013.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2014.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2015.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2016.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2017.log
[root@localhost test6]# chown :mail log2012.log 
[root@localhost test6]# ll
 A total of  604
---xr--r-- 1 root users 302108 11-30 08:39 linklog.log
---xr--r-- 1 root mail 302108 11-30 08:39 log2012.log
-rw-r--r-- 1 root users   61 11-30 08:39 log2013.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2014.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2015.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2016.log
-rw-r--r-- 1 root users   0 11-30 08:39 log2017.log

Example 4: change the owner and group of all files in the specified directory and its subdirectories

Command:

　chown -R -v root:mail test6

Output:

[root@localhost test]# ll
drwxr-xr-x 2 root users  4096 11-30 08:39 test6
[root@localhost test]# chown -R -v root:mail test6
 " test6/log2014.log "   The owner of has been changed to  root:mail
 " test6/linklog.log "   The owner of has been changed to  root:mail
 " test6/log2015.log "   The owner of has been changed to  root:mail
 " test6/log2013.log "   The owner of has been changed to  root:mail
 " test6/log2012.log "   The owner has been retained as  root:mail
 " test6/log2017.log "   The owner of has been changed to  root:mail
 " test6/log2016.log "   The owner of has been changed to  root:mail
 " test6 "   The owner of has been changed to  root:mail
[root@localhost test]# ll
drwxr-xr-x 2 root mail  4096 11-30 08:39 test6
[root@localhost test]# cd test6
[root@localhost test6]# ll
 A total of  604
---xr--r-- 1 root mail 302108 11-30 08:39 linklog.log
---xr--r-- 1 root mail 302108 11-30 08:39 log2012.log
-rw-r--r-- 1 root mail   61 11-30 08:39 log2013.log
-rw-r--r-- 1 root mail   0 11-30 08:39 log2014.log
-rw-r--r-- 1 root mail   0 11-30 08:39 log2015.log
-rw-r--r-- 1 root mail   0 11-30 08:39 log2016.log
-rw-r--r-- 1 root mail   0 11-30 08:39 log2017.log